TECH: Help - Wizard of Wor Power Regulator

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Wizard of Wor 5 volt power will not regulate. When first powered on it
starts at around 4.75 volts then slowly tapers off to about 3.5 volts.
I have replaced the electrolytic caps (just preventative maintenance)
but I cannot wrap my mind around this one. Adjusting the pot does not
alter the output. The other voltages adjust fine. Any help out there
for this one?

 

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Assumig you can read a schematic check the feedback line for the +5 and
the associated circuitry especially open resistors inline on the ps
board. The off chance that the +5 regulator (the actual semiconductor)
itself is out to lunch is also to be considered.

This is of course assuming you have already checked the board against
another power supply o isolate he possibility that the board is draggin
down the line.

- Matt

 

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Vintage Geek <daniel@mosmeyer.net> wrote:
: Wizard of Wor 5 volt power will not regulate. When first powered on it
: starts at around 4.75 volts then slowly tapers off to about 3.5 volts.
: I have replaced the electrolytic caps (just preventative maintenance)
: but I cannot wrap my mind around this one. Adjusting the pot does not
: alter the output. The other voltages adjust fine. Any help out there
: for this one?

Replace the 2n3055.

If the SG3532 is bad you're pretty much hosed (although with a little
work, you can make a lm723 work in its place).


--
Mark Spaeth mspaeth@mtl.mit.edu
50 Vassar St., #38.265 mspaeth@mit.edu
Cambridge, MA 02139
(617) 452-2354 http://rgvac.978.org/~mspaeth

 

[Guest]

Archived from groups: rec.games.video.arcade.collecting (More info?)

Replacing the 2n3055 did the trick.....much thanks to Mark. I am not
used to seeing this in a transistor. Usually, I expect to see them
either open or shorted.

Now, on to the monitor.